The present invention relates to a fastening device for component carriers in system housings and includes profiled fastening members that can be attached to the two forward vertical frame bars of the system housings as well as carrier elements that are displaceable in height, can be fixed to the profiled fastening members and are provided with a fastening thread for screwing on the component carriers which are equipped with front plates.
Component carriers serve to accommodate component groups, that is printed circuit boards provided with front plates, which are equipped with electrical and electronic components. A plurality of component carriers are arranged vertically above one another in system housings. Such system housings are composed of a supporting frame structure which includes wall, bottom and cover members and has a front opening that can be closed by a door through which the component carriers and component groups are accessible.
It is known to attach a profiled fastening member to fasten the component carriers to each of the two vertical front frame bars of the system housings, with a number of height adjustable and fixable carrier elements being provided at each profiled fastening member. These carrier elements are provided with fastening threads by means of which the component carriers are screwed at the desired height to the profiled fastening members and thus to the system housing.
Profiled fastening members equipped with rows of holes permit in a simple manner the screwing on of the component carriers at discrete heights. This poses no problems whatsoever as long as the component groups and their front plates are standardized with respect to their height dimensions or fall into a uniform grouping. Difficulties arise if component groups of different standards ar to be installed in uniform system housings. This is possible only if the carrier elements are displaceable and can be fixed to the profiled fastening members at any desired height.
Profiled rails have already been proposed which permit the fixing of the displaceable carrier elements at any height. These profiled rails are provided with T-shaped grooves in which threaded nuts can be displaced. The nuts are secured against slipping by means of profiled rubber members that are seated in the T-shaped grooves (unexamined published German Patent Application DE 3,620,870). The drawback is here that all threaded nuts must be pushed into the T-shaped grooves from the frontal faces of the profiled rails, that is, before they are installed in the frame bars of the system housings.
Also known is the use of spring tensioned sliding nuts for use at a predetermined location in a T-shaped groove. With such spring tensioned sliding nuts, displaceable carrier elements can be fastened at any desired height to correspondingly configured profiled rails. The rear face of each spring tensioned sliding nut is provided with a spring device that is supported at the bottom of the T-shaped groove, and the T-shaped groove as well as the spring tensioned sliding nut are dimensioned in such a way that the latter can be introduced from the outside into the T-shaped groove and in its interior can be pivoted into a rotated use position (German Patent No. 2,635,439). However, the establishment of the use position and displacement of the spring tensioned sliding nut is not possible manually but requires a tool.
Additionally, a device is known for fastening component carriers to the vertical frame bars of switching panels in which profiled fastening members are connected with the frame bars, each profiled fastening member being provided with a connecting web. Threaded, U-shaped sliding members are engaged on the connecting webs; these sliding members are adjustable in height and surround the connecting webs in a resilient manner for the purpose of holding them (European Patent No. 0,208,260). The manufacture of this device necessitates a certain amount of expenditures because requirements must be met for accurate fit.